The present invention relates generally to a refuelling nozzle and relates particularly, although not exclusively, to a refueling nozzle for mining equipment.
Australian complete patent application No. 47577/99 describes a refueling nozzle of a xe2x80x9cdry breakxe2x80x9d design. As shown in FIG. 1 the refueling nozzle 1 includes a housing 2 to which a muzzle section 3 is fitted at a forward end and an end cap 4 connected at a rearward end. The housing 2 includes a fuel inlet 5 to which a fuel hose (not shown) is connected, and a fuel outlet 6 formed in the muzzle section 3 of the housing 2. A fuel delivery passageway 7 is formed within the housing 2 between the inlet and outlet 5 and 6, respectively. A retainer 8 is designed to seat about the fuel outlet 6 and is coupled to a piston head 9 via a piston rod 10. The piston head 9 reciprocates within a rearward chamber 11 defined in the housing 2. The piston head 9 is actuated via a cocking handle 12 which pivots about the end cap 4. The cocking handle 12 is coupled to the piston head 9 via link members 13. The refueling nozzle 1 also includes a spring 14 housed within the end cap 4 and arranged to force the piston head 9 together with the piston rod 10 and the retainer 8 clear of the fuel outlet 6. The spring 14 is retained by a spring retaining member 15 which is threadingly fitted within the end cap 4. Screwing of the spring retaining member 15 adjusts the spring force imparted on the piston head 9 by the spring 14. The refueling nozzle 1 mates with a receiver 16 which is connected to a fuel tank (not shown). The receiver 16 includes a poppet valve 17 which is biased against and seals an outlet of the receiver 16. In operation the retainer 8 axially presses against and thus actuates the poppet valve 17 to permit the flow of fuel to the fuel tank.
The refuelling nozzle of Australian complete patent application No. 47577/99 suffers from the following drawbacks associated with the spring retaining member:
i) the force in the spring can unnecessarily and repeatedly be adjusted merely by removing an end fitting of the end cap and rotating the spring retaining member or in the alternative embodiment merely by rotating the spring retaining member through an access port provided in the end cap; and
ii) the threaded connection of the spring retaining member may displace over time and thus vary the spring force imparted on the piston head.
According to the present invention there is provided a refuelling nozzle comprising:
a nozzle housing including a fuel inlet and a fuel outlet between which is disposed a fuel passageway;
a reciprocating valve element being configured to sealably seat about the fuel outlet to prevent the flow of fuel through the fuel passageway;
a piston rod at opposing ends being connected to the reciprocating valve element and a piston, respectively, the piston being slidably housed in a piston chamber defined by the nozzle housing;
a spring being arranged at opposite ends to operatively cooperate with the piston and a spring retaining element, respectively, wherein the spring provides a biasing force to urge the reciprocating element via the piston and the piston rod to unseat from the fuel outlet; and
an end cap fitted to the nozzle housing, the end cap being arranged to house the spring and internally including a plurality of spaced apart recesses each being adapted to removably receive a locking element which engages the spring retaining element and, depending on the recess in which the locking element is located, vary the biasing force in the spring.
Preferably the recesses include a plurality of spaced apart annular recesses. More preferably the plurality of annular recesses are each in the form of an annular groove and the locking element is a C-clip which is removably received in one of the grooves. Generally the cap is provided with three or more of the annular grooves.
Typically the spring retaining element is generally cup-shaped and thus configured to locate about one of said opposite ends of the spring. More typically the cup-shaped retaining element includes an outwardly protruding flange which abuts the locking element.